How do I use those scooters?
After making one just put it in your inventory by pressing "Q".
Does it also work on robots you may ask.
I haven't tested it very well but from what I could tell there wasn't a noticeable differents between with or without, the only thing that's different is the sound (the robot won't ride it, it just makes the sound)
About the mallets.
You need 1 wooden mallet to build a totem.